Method and apparatus for perforating well casings



Aug, 2@ 94@ R; M. RIDLEY 2,212,044

METHOD AND APPARATUS FR PERFORATING WELL CASINGS /OfL7 Filed July 24,1959 Hiya/g77 @A www Patented ug. 20, 1940 UNITED sTATEs METHOD ANDAPPARATUS FOR PERFORAT- ING WELL CASIN GS Ralph M. Ridley, Whittier,Calif., assigner of dne- A`third to Howard W.` Stepp and one-third toTillman JiileS, both 0f Whittier, Calif.

Application July 24, 1939, Serial No. 286,194

18 claims.

This invention relates to Well tools and well production methods, andrelates more particularly to a tool and method for perforating Wellcasing. A general object of this invention is to provide a practical,eifective, gun perforator and novel projectiles for the same, and arapid, efficient method for perforating well casing.

It is often necessary to perforate a well casing at a productive zone ofthe well following the setting and cementing of the casing. Tools havebeen developed that re projectiles through the Wall of a set casing toperforate the same. These so-called gun perforators are successful andeffective but their use is restricted to wells that are more or lessfree of sand. The projectiles red by the gun perforators make largeholes or perforations in the casing and where the oil or other produceduid carries alarge amount of sand, excessive quantities of sand areadmitted by the large perforations and the well soon becomes sanded up.

l Another object of this invention is to provide a gun perforator thatis useful and effective in the perforation of casing installed in Wellswhere the produced iiuid is accompanied by large percentages of sand andother solid matter.

Another object of this invention is to provide a gun perforator thatvforms or provides perforations in the casing that are reduced orlimited in fluid capacity to restrict the entrance of sand and othersolid matter into the casing.

Another object of this invention is to provide a gun perforator lthatautomatically beans, lines, or bushes the perfoations'in the casing toreduce their size andfiuid capacity, and to assure uniformity in thecapacity and shape of the several perforations.

Another object of this invention is to provide a gun perforator of. thecharacter mentioned that inserts the beans or bushings in theperforations in such a manner that they are securely and dependably xedin the perforations to form re- .ducers and wear resistant linings forthe perforations.

Another object of this invention is to provide a gun perforator that mayhandle and install perforation beans or bushings of hard material thatare very resistant to wear to prevent or reduce theenlargement of theiiuid admitting openings by the abrasive action of the solid matter inthe produced uid.

Another object of this invention is to provide a novel projectile forcasing perforators that embodies a trailing part that lodges in theperforation when the projectile pierces the well casing,

and that forms a' reducer, bean or bushing in the perforation.

Another object of this invention is to provide a projectile of thecharacter mentioned in which flciently high to assure the full piercingof the casing by the projectile. Y

Another object of this invention is to provide 10 a cartridge for a gunperforator that embodies the projectile, the above-mentioned perforationbushing, the charge container and the squib associated as a singleiiuid-tight unit that is easily handled and quickly loaded'in the gununit of 15 the perforator.

A further object of the invention is to provide a method for perforatingwell casing in which the casing is perforated after being set in thewell and the resultant perforations are provided with liningsor bushingsfor reducing the fluid capacity.

The various objects and features of my inventionwill be fully understoodfroml the following detailed description of. typical preferred forms 26and applications of the apparatus and manner of carrying out the Imethod ofmy invention, throughout which description reference is made tothe accompanying drawing, in which:

Fig. 1 is a side elevation of a gun perforator $0 embodying the presentinvention. Fig. 2 is an enlarged, vertical, detailed, sectional view ofthe perforator illustrating one of the gun units and tion. Fig. 5 is aview similar to Fig. 4 illustrating still another type of projectile.Fig. 5a is a trans- 40 verse, sectional view taken on line tia-5a of.Fig.

5. 'Fig. 6 is an end View of one of the trailers or bushings after ithas left the gun unit, and Fig. 7

is a fragmentary, longitudinal, sectional View of a Well casing,illustrating a lining or bushing set 45 in a perforation in the casing.

'Ihe perforator of the present invention illustrated in Figs. 1, Zand 3may be said to comprise, generally, a body Ill, a plurality of gun unitsIl carried by the body Ill, and improved 50 cartridges I2 for, the gununits.

The body l0 forms the carrier for the gun units Il and the other partsof the tool and is adapted to be run into and out of the well. Inpractice the body l0 may be an elongate member 55 of generallycylindrical shape provided with a suitably rounded lower end. A ropesocket I3 is provided on the upper end of. the body for securing thetool to a line L for running the tool into and out of the well. One ormore openings or sockets I4 are provided in the body I0 to receive thegun units II. In the case illustrated there is a plurality oflongitudinally and circumferentially spaced sockets I4. The sockets I4may be arranged in longitudinal rows with the sockets of the adjacentrows in vertically offset relation. The sockets I4 are cylindrical boresopen at the exterior of the body I0 and fully closed at their innerends. Longitudinal external grooves I5 are provided in the body I0 to beadjacent the mouths of, the sockets I4. Transverse notches I6 mayconnect the grooves I5 with the mouths of the sockets I4. The grooves I5extend upwardly to the rope socket I3.

The gun units II are arranged in the sockets I4 to receive thecartridges I2. The gun units II are preferably alike and each includes abody or block I1 and a barrel I8. The blocks I'I are cylindricalelements proportioned to flt the sockets I4. Pins or wedges I9 arepassed through transverse openings 20 in the body I0 and cooperate withnotches 2I in the blocks I1 to removably secure the blocks in thesockets. Central longitudinal openings 22 enter the blocks I'I fromforward ends of the blocks. The inner portions of the openings 22 arereduced in diameter to form chambers 23 and to provide forwardly facingannular shoulders 24. The chambers 23 are fully closed at their innerends.

The barrels I8 are tubular parts removably secured in the openings 22 ofthe blocks I1. tIn the preferred construction the barrels I8 arethreaded in the outer portions vof the openings 22. The barrels I8 andthe walls of the openings 22 have coarse, heavy threads. The walls ofthe openings 22 and the inner portions of the barrels I8 are preferablyunthreaded or plain. The outer portions of the barrels I8 are polygonalfor engagement by wrenches and the outer ends of the blocks I'I arerecessed to render the polygonal parts of the barrels accessible. Thebarrels I8 are provided with central longitudinal bores 25. The bores 25are cylindrical except at their inner end portions where they aretapered or flaring. In accordance with the invention the bores 25 arerifled, being provided with longitudinal grooves 2B. The grooves 26 arecircumferentially spaced and are of like size and shape. The grooves 26may either be straight or spiralled. In the form of the inventiondescribed the grooves 26 are pitched or spiralled. The grooves 26 extendinwardly from the mouths of the bores 25 to the tapered inner parts ofthe bores where they die out. l

A cartridge I2 is loaded in each gun unit I I and each cartridgeincludes a projectile 28, a perforation lining member or bushing 29 onthe projectile 28, and a container 30 holding a charge 3|. for firingthe projectile. The projectiles 28 are arranged in the bores 25 and aredesigned to pierce or perforate the well casing. Fig. 'I of the drawingillustrates av portion of well casing C' having a perforation P formedby a projectile 28. The projectiles 28 are lgenerally cylindricalelements `proportioned to bear on or fit the lands 32 of the bores 25,which lands occur between the grooves 26. The forward ends of theprojectiles 28 are pointed or otherwise shaped to pierce the casing C.The rear ends of the projectiles 28 are flat and provided withrearwardly -formity to the rifled bores 25.

projecting stems 33 of reduced diameter. In the form of the inventionbeing described, central longitudinal openings 34 extend through theprojectiles 28. The openings 34 extend from the forward ends of theprojectiles to the rear endsof the stems 33. The projectiles 28 may beformed of any selected material, for example, they may be constructed ofhardened steel.

The perforation lining members or bushings 29 are important features ofthe invention. The bushings 29 are carried by the projectiles 28 and aredesigned to lodge in the perforations P formed in the casing C bythe'projectlles. The lining members or bushings 29 are ring-like orspool-like elements arranged on the stems 33 of the projectiles 28. Thebushings 29 are secured to the projectiles 28 in such a manner that theyare fired together with the projectiles and become detached from theprojectiles as the projectiles pass through the casing C. In practicethe bushings 29 may be press-tted on the stems 33 in such a manner thatthey travel with the projectiles until they enter the perforations P.The perforation lining members or bushings 29 are adapted to fit thetapered inner portions of the bores 25, being provided with taperedperipheries.

In the form of the invention being described the bushings 29 are made ofa formable or malleable material such as brass, copper, bronze, oralloys of such materials so that the force developed `by the charges 3|shapes them into con- This provides the bushings 29 with pluralities ofcircumferentially spaced lugs 35. Fig. 6 of the drawing illustrates abushing 29 after it has left a barrel bore 25. It is to be understoodthat the perforation lining members or bushings 29 are initially formedwithout the lugs 35 and that the high pressure developed by the charges3I drives the bushings 29 through the rifled bores 25 so that the boresact as dies. The rifles or grooves 26 of the bores 25 receive the metalof the bushings 29 as the bushings are forced out through the bores andserve to shape the spaced lugs 35. The explosive pressure behind thebushings 29 has no tendency to detach the bushings from the stems 33 andthe bushings leave the bores25 with the projectiles. The projectiles 28of course form perforations P whose diameter is substantially equal tothe diameter of the projectiles, and when the members or bushings 29,carried by the projectiles, encounter the perforations P their lugs 35bind or stick in the perforations. The lugs 35 may be flattened downthrough their contact with the walls of the perforations P or may remainas ears or projections on the bushl ings.

'I'he wedging or lodging of the lugs 35 in the perforations P stops thebushings so that the bushings become detached from they projectiles andremain in the perforations P while the projectiles continue outwardly toperforate the surrounding cement where the same is present. 'I'hus thebushings 29 remain in the perforations P asreducers, beans, or linings.In this connection it is to 'be noted that the size of the openings 36in the bushings 29 depends upon the diameter of the projectile stems 33and that the stems 33 may be formed to provide fluid admitting openings36 in the casing C of any selected diameter. The openings 36 are, ofcourse, considerably smaller than the perforations P and the bushings 29serve to prevent or limit the entrance of gravel, sand particles, etc.into the well. y

The containers 30 occupy the chambers 23 and are connected with thebushings 29 and the projectiles 28. The containers 30 are tubularcylindrical elements closed at their rear ends by plugs 3'I. 'Ihe plugs31 are inserted following the loading of the powder charges 3I.-outwardly projecting annular anges 38 are provided on the forward endsof the containers 30 and are adapted to bear against the shoulders 24. Acarrier plate or element 39 is arranged across'the mouth or outer endofv each container 30. The elements 39 are secured and sealed to theanges 38 by welding, brazing, sweating, or the like. The elements 39 areperforate or annular having central openings 49 in alignment with theprojectile openings 34. 'Ihe elements 39 serve to connect the projectileassemblies .with the containers 30. The rear ends of the bushings 29 aresecured to the elements 39 by sweating, or the like. The forward facesof the elements 39 are engaged by the rear ends of the barrels I8 andwhen the barrels are threaded in and tightened `down the elements 39 andthe flanges 38 are clamped between the barrels I8 and the shoulders 24.This provides effective fluid-tight and pressure-tight seals at theforwards ends of the charge containers 3|. It will be observed that thecartridges I2 are complete assemblies that may be easily and quicklyloaded in the gun units II.

The means for firing or igniting the powder charges 3| include ignitersor squibs 4| in the containers 30. Wires 42 are connected with thesquibs 4| and pass outwardly through the openings 40 and 34 to themouths of the bores 25. Seals 43 are provided in the outer portions ofthe openings-34 to seal about the wires 42 and prevent the leakage offluid through the openings. The wires 42 are trained through notches 44in the outer parts of the barrels I8 and through the notches I6. Thewires 42 continue upwardly through the grooves I5 to suitable means forcontrolling the ignition of the squibs 4|. 'Ihe present invention is notprimarily concerned with the means or method of controlling the ignitionof the squibs 4| As indicated in Fig. 1 of the drawing, the ignitionwires 42 may enter the rope socket I3 and may connect with a controllingdevice or distributor 45 governed by a'control wire 46 associated withthe line L.

In the operation of the perforator described above, and in carrying outthe method of thev invention, the gun units are loaded with thecartridges I2 and the body IIJ carrying the units Il is lowered into thewell on the line L. When the perforator is in the portion of the casingto be perforated the device or distributor 45 is operated to ignite thesquibs 4|. ferred to ignite the squibs 4I in succession so that theprojectiles 28 are successively fired. When apowder charge 3| is firedby its squib 4I the charge builds up a high pressure. The element 39resists the immediate discharge of this pressure and the tapered bushing29 fitting the tapered part of the bore 25 oers substantial resistancetothe pressure. When a very high pressure has built up, the element 39fails and the pressure acting on the bushing 29 shapes the bushing tothe riiied bore 25 and drives the bushing and its projectile 28 from thebarrel I8. The heat generated by the powder charge 3| may assist in theyforming ofthe bushing 29. The bushing 29 forced through the ried-bore 25has spaced peripheral lugs 35 when it leaves the bore It is usuallypre-y 25. The projectile 28 pierces the casing C yto provide aperforation? and the bushing 29 travel- 'ing with the projectileencounters or enters the perforation. The lugs 35 on the bushing lodgein the perforation P and this stops the bushing. The lugs 35 are verytightly driven into the perforation P and the bushing 29 is securelyfixed in the perforation. The bushing 29 thus remains as a permanentreducing element or screen element 'of the casing C. 'I'he opening 36 ofthe bushing 29 may be of a predetermined or selected diameter tratedsomewhat modifled forms of gun units II and cartridges I 2.

The construction shown in Fig. 4 of the drawing includes a barrel |88having a ried bore 25a whose inner portion' may be ared or tapered inthe same manner as the bore 25. The projectile 28a employed in the bore25a may be the same as the projectile 28 and ts the bore. A perforationlining or bushing 29a is arranged on the stem 33a of the projectile 28a.The bushing 29a is press-fitted on the stem 33a or is otherwisedetachably connected with the projectile 28a. The bushing 29 is formedof steel, or the like, so that an electrolytic action will not be set upbetween the bushing and the steel casing when the bushing is lodged inthe perforation. The body of the 'bushing 29 is of substantially thesame diameter as the bore 28a to pass through the bore and lugs 50 areprovided on the periphery of the bushing.A The lugs 50 are arranged andproportioned to pass through the grooves 26 of the rified bores 25a andare intended to catch or lodge ln the perfora- .21

4with the projectile. The lugs 50 pass out through the grooves 26a. 'Asthe projectile 28 passes through the wall of the casing C the lugs 50strike the wall of the perforation formed by the projectile andthusvstopl the bushing 29H. The bushing 29a vis thus detached from theprojectile 28a and the projectile continues outwardly. The

` Figs. 5 and 5a has a plain unried bore 25b.re ceiving 'a projectile28h. 'llhe vprojectile 28b has a suitably pointed forward end and itsinner end has a reduced' stem 33h. In this form of the invention spacedllongitudinal grooves 60 are pro-v vided in the projectile 28h. Thegrooves 60 are continuous and extend from the inner end of theprojectile 28b to the pointed forward end where they die out. When theprojectile 28D is fired to pierce the casing, the grooves 60 form. orleave lugs on the wall of the perforation. A perforation liner orbushing 29b is detachably arranged on the stem 33a to line theperforation formed by the projectile 28. The bushing 29b is plain orungrooved and suitably fits the bore 25h. When the projectile 28b isfired the bushing 29b travels with the -projectile and| lodges in theperforation formed in the casing by the projectile. The bushing 29bencounters the lugs formed on the y wall of the perforation by thegrooves 60 and is stopped -by the lugs, while the projectile continueson through the casing, cement and earth forma.- tion. The lugs on thewall of the perforation stop and hold the bushing so that the bushing isretained in the perforation to act as a reducer or liner vfor theperforation. Instead of forming grooves in the projectile as shown inFigs. 5 and 5a the projectile may .be made slightly smaller in diameterthan the bore .25W and the bushing 29b so that the bushing will lodge inthe perforation formed in the casing by the smaller projectile.

lHaving described only typical preferred forms of apparatus and of themanner of carrying out the method of my invention', I .do not wish to belimited or restricted to the specific details herein set forth, but wishto reserve to myself any variations or modifications that may appear tothose skilled in the art or fall Within the scope of the followingclaims:

Having described my invention, I claim:

1. A well tool for .perforating well casing comprising a body, a gununit carried by the body, a projectile in the gun unit, a charge forfiring the projectile, and a perforate trailer associated with theprojectile to be fired therewith and formed to lodge in the perforationformed in the casing by the projectile.-

2. A well tool for perfor-ating Well casing comprising a body, a gununit carried by the body, a projectile in @e gun unit, a charge forfiring the projectile, and a tubular bushing ybehind the projectileadapted to be red with the projectile to lodge in the opening formed inthe casing by the projectile.

3. A well tool for perforatlng Well casing comprising a body, a gun unitcarried by the body, a projectile in the gun unit, a charge for firingthe projectile so that the projectile forms a perforation in the casing,and a bushing for the perforation carried :by the projectile to line theperforation.

4. A well tool for perforating well casing comprising a body, a gun unitcarried by the body, a projectile in the gun unit, a charge for firingthe projectile, a stem on the rear end of the projectile, and a tubularmember detachably carried on the stem and designed to remain in theperforation as a liner therefor as the projectile pierces the 'casingwall.

5. A tool for perforating well casing comprising a body tovbe run intothe casing, a gun unit carried by the body and including a ybarrelhaving a bore and grooves in the wall of the bore, a projectile to bered from the bore to form a perforation in the casing, means for firingthe projectile, and a bushing for the perforation associated with theprojectile to be ilred therewith and designed to have parts that passthrough the grooves and lodge in the .perforation to stop the bushing inthe perforation.

6. A tool for perforating `well casing comprising a body to be run intothe casing, a gun unit carried by the .body and including a barrelhaving a .bore and grooves in the wall of the Ibore, the inner portionof the bore being enlarged, a projectile to be fired from the bore toform a perforation in the casing, a charge for ring the proj ectlle, anda formable member in the enlarged portion of the bore and associatedwith the projectile to be red therewith and to be formed throughcooperation with the bore and grooves to have parts which retain it inthe perforation.

7. A tool for perforating well casing comprising a body to be run intothe casing, a gun unit carried by the body and including a barrel havinga bore and a groove in the wall of the bore, the inner portion of thebore being flared, a projectile to be red from the bore, means forfiring the projectile, and a tapered member in the flared portion of thebore associated with the projectile to be fired vtherewith andcooperating with the flared portion of the 'bore to resist the pressuredeveloped by said means until the member is formed to pass through thebore and itsV groove and Ythus have a lug for retaining the member inthe perforation.

* 8. A tool for perforating well casing comprising a body to be run intothe casing, a gun unit carried by the body and including a barrel havinga bore and a groove in the wall of the bore, the inner 4portion of thebore being enlarged, a projectile to be fired from the bore, means forfiring the projectile, a member detachably connected with the projectileto be fired therewith, and a lug on the mem-ber adapted to pass throughthe groove and to cooperate with the perforation to retain the member inthe perforation.

9. A tool for perforating well casing comprising a body to be run intothe casing, a gun unit carried .by the body and including a barrelhaving a bore, 'the inner portion of the bore being enlarged, aprojectile in the -bore having a longitudinal opening, a powder chargein the gun unit for firing the projectile, means for firing the chargeincluding an ignition wire extending through the opening to the charge,and a liner for the perforation in the enlarged portion of the boreadapted to be fired with the projectile to lodge in the perforation.

l10. A well tool for .perforating well casing comprising a body, a. gununit carried by the body, a projectile in the gun unit, a charge forring the projectile, a reduced stem on the rear end of Athe projectile,the projectile having a longitudinal opening which extends through thestem, a bushing removably arranged on the stem to be fired with theprojectile and adapted to lodge in the perforation formed -in the casingby the projectile, and means for ring the charge including an ignitionwire extending through the opening.

11. A' tool for perforating well casing comprising a body to be run intothe casing, a gun unit carried by the body and including a barrel havinga bore, the inner portion of the bore being enlarged, and a cartridge inthe gun unit including a projectile in the bore, a bushing member in theenlarged portion of the bore associated with the projectile to be firedtherewith and designed to remain in the perforation in the casing, acarrier element connected to the member, and a charge container securedto and sealed with the carrier element.

12. In a casing perforator for perforating a Well casing in a weil, aprojectile for piercing the casing, and a bushing detachably arranged onthe projectile'I to lodge in the perforation in the casing.

13. In a perforator for perforating well casing, a projectile forpiercing the casing, and a tubular bushing element detachably connectedwith the rear end of the projectile to lodge in the perforation in thecasing,

14. In a casing perforator to be lowered into a 9,212,044 well casing, aprojectile for piercing the casing,

and a tapered bushing member oi' formable material detachably associatedwith the projectile to lodge in the perforation in the casing.

15. In a. casing pei-forator for perforating a casing in a. well, aprojectile for piercing the casing, and a bushing element detachablyarranged on the projectile to lodge in the perforation in the casing.the said element having projecting lugs.

16. In a casing perforator for perforating a casing in a well. aprojectile for piercing the casing. the 'projectile having alongitudinal groove,

and a bushing element detachably arranged on the projectile to lodge inthe opening formed by the projectile.

17. The method of perforating a casing set in a well comprising nring aprojectile through the wall ofthe casing to form s. perforation therein,and lodging a bushing in the perforation.

18. The niethod of perforatlng a casing set in a well comprising ilringa projectile through the wall of the .casing to form a perforationtherein. and firing a perforate element to' lodge in the perforation toform a lining therefor.

RALPH M. RIDLEY.

